Loosely adapted another recipe to make this - cinnamon was nice but I think next time I would use less or leave it out altogether.
3/4 cup white long grain rice
3 & 1/2 cups milk
3 tbs powered milk
1/2 cup white sugar
3/4 tsp cinnamon
1 pinch salt
3 tbs butter (I grated mine into the mix)
Grease the inside of the slow cooker.
Stir in all the other ingredients.
Cook on high for 2 &1/2 to 3 hours.
Check after the lesser time - it will also keep cooking after the slow cooker is turned off...so turn it off when there is still a bit of liquid - it will solidify on standing.